1. Technical Field
The technology disclosed herein relates to a voice emphasis device comprising a correlation component removal filter circuit.
2. Background Information
A method has been proposed in the past for emphasizing voice sound by finding a residual signal by passing an input signal through a reverse filter formed based on a linear prediction coefficient obtained by subjecting the input signal to linear predictive coding, and then inputting the residual signal through a filter formed on the basis of a linear prediction coefficient corrected so as to emphasize formants (see Japanese Laid-Open Patent Application 2010-055022, 2005-287600 and 2007-219188). However, even if formants are emphasized by processing vowels that have a high signal level and are easy to hear, as with this method, it is difficult to improve voice clarity. Meanwhile, consonants tend to be masked by vowels because they have a lower signal level than vowels, and the frequency spectrum of consonants extends up to a high frequency, which means that people who have trouble hearing higher frequencies will have trouble hearing consonants. In view of this, a method has been proposed for improving voice clarity by amplifying or repeating a number of times those consonants extracted from voice sound by detecting a section in which the amplitude of a voice signal is at or below a specific value (see Japanese Laid-Open Patent Application 2005-287600 and 2007-219188).